This blog will feature comments on apicultural observations by Dr. Malcolm T. Sanford, Retired Extension Apiculturist, University of Florida, publisher of the Apis Newsletter.

Monday, December 1, 2008

More on Pine Honey Production

As its name implies much of the attention at the Pine Honey Congress just completed in Mugla, Turkey was devoted to selling and producing the honeydew crop. In this regard, papers from investigators in nearby Greece were important as well as those from Turkish researchers. Pine honey is honeydew collected from the complex of the scale insect Marchalina Hellenica feeding on pine trees (Pinus sp.). The scale has to imbibe so much liquid from the plant’s phloem that it is forced to excrete a good deal of sweet juice that can be collected by honey bees. The honeydew honey from pines is highly sought after and commands a good price, but it requires special management; is not easy to characterize for export purposes, and thus is a great candidate for economic adulteration.

There is no codex standard for this pine honey, as Dr. Stefan Bogdanov of Bee Product Science in Switzerland confirmed in a review of the subject. Characterizing the material does encompass similar analyses, including organoleptic (taste, smell), and pollen and chemical analyses, as well as electro conductivity. However, because there is no internationally-valid criteria to distinguish pine honey as there is for unifloral honey in the E.U., the International Honey Commission is currently working on the issue. Another paper by Banu Yücel reported that because 92 percent of Turkish pine honey was produced in the Mugla area and 15,000 tons were exported each year to the EU, a specific codex should be created for this product.

A paper by Dr. Chysoula Tananaki investigated the possibility of using volatile compounds measured via Gas Chromatography and Mass Spectrometery on pine honeys in both Greece and Turkey. Specific compounds including 3-carene were found only in Turkish pine honey, suggesting these might be markers for the product. It was nevertheless concluded that although useful, they should continue to be used only in conjunction with physiochemical and organoleptic methods.

Dr. Sofia Goundari reported on a six-year study of the scale, Marchalina Hellenica (M.h.) in Greece. Aspects studied included morphology, taxonomy, evolution, life cycle and population density in relation to life cycle in five regions: Crete, Attiki, Evia, Chalkidiki, and Thessaloniki. It is concluded that:

M.h. has one generation per year.

The appearance of adults and egg-laying is from 25 March through 25 April.

There are very few males, although on Crete some large populations have been found.

Egg laying in both lab and field has been documented to averag 30 days.

The number of eggs by an individual can reach 400, with an average of 222.

All first instar nymphs become attached to pine trees and begin secreting honey dew by 15 June.

Further ecdyses (developmental changes) occur at the end of August and in October.

The resulting third instar hibernates and continues to secrete honey dew, but the bees often cannot collect this material due to inclement weather.

The developmental times of M.h. nymph are fairly constant over the five regions, but the honeydew secretion varies considerably. Thus, the weather conditions and the health of the trees determine to a great extent the amount of honeydew produced. This makes it difficult for beekeepers to figure out when to move colonies; they can be caught out if the flow does not occur as projected. Dr. Goundari suggests beekeepers in Greece and Turkey develop an information network as found in Germany and other places to help with this decision making.

The advantages of pine honey for beekeepers includes the fact that the harvest is relatively stable from year to year, large numbers of colonies in holding yards do not appear to affect the flow (controversial for some), the flow helps to winter honey bees (perhaps, although the honeydew is not considered optimal for bee nutrition), there is little danger of pesticide damage (the trees are not sprayed), and robbing in limited. The disadvantages include colonies not going into winter in the best possible shape (the queen can easily become honeydew bound and unable to lay eggs) and the spread of disease is enhanced since colonies are placed in very large congregations.

Given the biology noted above, Dr. Goundari provided information on how to exploit the M.h. scale in terms of when and where to move colonies and how to manage them specifically for pine honey production. Before moving, colonies should be strong, treated for Varroa, well fed (syrup and pollen) and they should be “hungry,” not have too many empty frames. In order to determine the optimum time to move, “sentinel” colonies should be placed in areas and monitored for incipient flows.

After the colonies are moved into the honeydew, the management shifts to monitoring combs and pulling them as they fill up – only one brood chamber is used and combs are taken from it. Too much space (the reason supers are not uniformly used) can mean the bees will put the honeydew in small patches all around the frame instead of filling it up uniformly. This seems to parallel to some extent bees managed for section comb honey where they are reluctant to enter the sections unless “force” to do so. Clearly the art of managing honeybees for pine honey is just as demanding, if not more so, than producing good section comb honey.